Re: Hummingboard DTB (imx6)
On Sunday 19 November 2017 16:20:33 Rainer Dorsch wrote:
> Hello,
>
> the Debian kernel does not work at all with the SPI interface of the
> my Hummingboard, see here
>
> http://forum.solid-run.com/viewtopic.php?f=10&t=3406&p=22586#p22586
>
> I am not a dtb expert, but is in the debian dtb spi support included?
>
> There is at least some indication....
>
> spi0 =
> "/soc/aips-bus@02000000/spba-bus@02000000/ecspi@02008000"; spi1 =
> "/soc/aips-bus@02000000/spba-bus@02000000/ecspi@0200c000"; spi2 =
> "/soc/aips-bus@02000000/spba-bus@02000000/ecspi@02010000"; spi3 =
> "/soc/aips-bus@02000000/spba-bus@02000000/ecspi@02014000";
>
> Somebody claims that the Fedora kernel supports SPI flawless (with the
> proper dtb file).
>
SPI support is labeled as broken in debian. And likely will remain so
until some one who understands it decides to work on it. Some of the
problem is in obtaining the headers for the gpio that is on the
individual card.
Decent SPI support, as in error free writing at 41 megabaud, in 32 bit
packets, and reading back, error free, the results at 25 megabaud, from
a Mesa 7i90HD interface card over a 1" long cable, is currently done
ONLY from a user-space module that is now part of linuxcnc, and ONLY on
a raspberry Pi 3b. This code can probably be made to run on other
platforms, but so far I haven't even been successful at removing the "am
I running on a pi-3b checks". After that, then figure out how to get the
headers for the gpio part of the SoC thats on the boards you have, of
which there are apparently at least a dozen mutually incompatible
versions just from Broadcom. I'd certainly bow and give homage to the
person who can take rpspi.c and its limited header dependencies, rename
it to rkspi.c and make it run on the rock64 board at similar speeds.
Although its not that much faster than a pi, it comes without the very
small funnel that all non-gpio generated data must get (its an internal
usb2 hub) thru on a pi, and which throws away keyboard and mouse events
in wholesale amounts. The rock64, compared to the pi, feels to be at
least 5x faster than the pi will ever be because of this one difference
in internal architecture.
A universal driver would be nice, but I suspect the best is going to be a
driver per platform. There is not a universal gpio, yet. Maybe another 5
years for the winner to be shook out of the bushes far enough to become
a standard.
The source code is out there, a git pull away, and its gpl. All it needs
is to convert the rpi3 checks into something that includes the proper
header to assign gpio pins in a std configuration for that board. One
that is pin compatible with the interface boards already out there.
At my age, 83, the wet ram isn't up to that anymore.
Good luck.
> Any hint is welcome...
>
> Thanks
> Rainer
Thanks for the chance to expound, Rainer.
Cheers, Gene Heskett
--
"There are four boxes to be used in defense of liberty:
soap, ballot, jury, and ammo. Please use in that order."
-Ed Howdershelt (Author)
Genes Web page <http://geneslinuxbox.net:6309/gene>
Reply to: